Replace GitHub Gist's, YouTube, Vimeo URLs with their embed equivalent

embed.js

/**
 * This function accepts text which is to be transformed into HTML. When
 * it encounteres a line which simply contains a single URL it will replace
 * that URL with an HTML tag to embed the corresponding resource.
 *
 * Supported services:
 * - GitHub Gists
 * - YouTube Videos
 * - Vimeo Videos
 */
const GIST = /^(https:\/\/gist\.github\.com\/[a-zA-Z0-9_-]+\/[a-z0-9]+)$/gm;
const VIMEO = /^https:\/\/vimeo\.com\/([0-9]+)$/gm;
const YOUTUBE = /^https:\/\/www\.youtube\.com\/watch\?v=([0-9A-Za-z-_]+)$/gm;

const WIDTH = 640;
const HEIGHT = 480;

function gist(input, width, height) {
  return input.replace(
    GIST,
    '<script src="$1.js"></script>'
  );
}

function vimeo(input, width, height) {
  return input.replace(
    VIMEO,
    `<iframe class="video-embed" width=\"${width}\" height=\"${height}\" src=\"https://player.vimeo.com/video/$1?app_id=122963\" frameborder=\"0\" allow=\"fullscreen\" allowfullscreen></iframe>`
  );
}

function youtube(input, width, height) {
  return input.replace(
    YOUTUBE,
    `<iframe class="video-embed" width=\"${width}\" height=\"${height}\" src=\"https://www.youtube.com/embed/$1?feature=oembed\" frameborder=\"0\" allow=\"fullscreen\" allowfullscreen></iframe>`
  );
}

const TASKS = [ gist, vimeo, youtube ];

module.exports = function (html, width, height) {
  for (let task of TASKS) {
    html = task(html, width || WIDTH, height || HEIGHT);
  }

  return html;
};

Example Usage:

const embed = require('./embed.js');
const HTML = `
https://www.youtube.com/watch?v=Y3uyfm9P1jQ
https://www.youtube.com/watch?v=nbY2ukvFFNc
https://www.youtube.com/watch?v=eejnHjgiy3I

https://vimeo.com/190942156
https://vimeo.com/148970924

no touch https://vimeo.com/148970924
https://vimeo.com/148970924 no touch

https://gist.github.com/tlhunter/d554a6b90ac53f61c16285a89a9b8f2e
https://gist.github.com/kesor/2622346
`;
const result = embed(HTML, 1280, 960);

console.log(result);

Example Output:

<iframe class="video-embed" width="1280" height="960" src="https://www.youtube.com/embed/Y3uyfm9P1jQ?feature=oembed" frameborder="0" allow="fullscreen" allowfullscreen></iframe>
<iframe class="video-embed" width="1280" height="960" src="https://www.youtube.com/embed/nbY2ukvFFNc?feature=oembed" frameborder="0" allow="fullscreen" allowfullscreen></iframe>
<iframe class="video-embed" width="1280" height="960" src="https://www.youtube.com/embed/eejnHjgiy3I?feature=oembed" frameborder="0" allow="fullscreen" allowfullscreen></iframe>

<iframe class="video-embed" width="1280" height="960" src="https://player.vimeo.com/video/190942156?app_id=122963" frameborder="0" allow="fullscreen" allowfullscreen></iframe>
<iframe class="video-embed" width="1280" height="960" src="https://player.vimeo.com/video/148970924?app_id=122963" frameborder="0" allow="fullscreen" allowfullscreen></iframe>

no touch https://vimeo.com/148970924
https://vimeo.com/148970924 no touch

<script src="https://gist.github.com/tlhunter/d554a6b90ac53f61c16285a89a9b8f2e.js"></script>
<script src="https://gist.github.com/kesor/2622346.js"></script>